<!DOCTYPE html>
<html>
	<head>
		<meta charset="UTF-8">
		<title></title>
		<script>
			function aa(){
				var s = eval('2+3');
				alert(s);
			}
		</script>
	</head>
	<body>
		<a href="javascript: aa()">点击</a>
		<button onclick="aa()">按钮</button>
	</body>
</html>
